package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSON;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.conditions.query.QueryChainWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.geo.CustomMetric;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;
import java.util.function.Function;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 * 服务实现类
 * </p>
 */
@Service
@SuppressWarnings({"all"})
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Autowired
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透
        //Shop shop = cacheClient.
        //        queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, ids-> getById(ids),CACHE_SHOP_TTL,TimeUnit.MINUTES);

        //互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);

        //逻辑过期解决缓存击穿
        Shop shop = cacheClient.
                queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class,ids-> getById(ids) ,CACHE_SHOP_TTL,TimeUnit.MINUTES);

        if (shop == null) {
            return Result.fail("店铺不存在!");
        }
        return Result.ok(shop);
    }

    private final static ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

    /**
     * queryWithLogicalExpire(Long id)利用逻辑过期来解决缓存击穿问题
     */
    //    public Shop queryWithLogicalExpire(Long id) {
//        //1.从redis中查询缓存
//        String key = CACHE_SHOP_KEY + id;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断缓存是否命中
//        if (StrUtil.isBlank(shopJson)) {
//            //3.未命中
//            return null;
//        }
//        //4.命中，需要把json反序列化成对象
//        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
//        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
//        LocalDateTime expireTime = redisData.getExpireTime();
//
//        //5.判断是否过期
//        if (expireTime.isAfter(LocalDateTime.now())) {
//            //5.1未过期，返回商铺信息
//            return shop;
//
//        }
//        //5.2过期，则需要缓存重建
//        //6.缓存重建
//        //6.1获取互斥锁
//        String lockKey = LOCK_SHOP_KEY + id;
//        boolean tryLock = tryLock(lockKey);
//        //6.2判断是否获取锁成功
//        if (tryLock) {
//            //6.3成功，开启独立线程，实现缓存重建
//            String s = stringRedisTemplate.opsForValue().get(key);
//            RedisData redisData2 = JSONUtil.toBean(s, RedisData.class);
//            Shop shop2 = JSONUtil.toBean((JSONObject) redisData2.getData(), Shop.class);
//            LocalDateTime expireTime2 = redisData2.getExpireTime();
//            if (expireTime2.isAfter(LocalDateTime.now())) {
//                return shop2;
//            }
//
//            CACHE_REBUILD_EXECUTOR.submit(() -> {
//                try {
//                    //重建缓存
//                    this.saveShop2Redis(id, 20L);
//                } catch (Exception e) {
//                    throw new RuntimeException(e);
//                } finally {
//                    //释放锁
//                    unLock(lockKey);
//                }
//            });
//        }
//        //6.4返回过期的商铺数据
//        return shop;
//    }

    /**
     * queryWithMutex(Long id)利用互斥锁来解决缓存击穿问题
     *
     * @param id
     * @return
     */
    //    public Shop queryWithMutex(Long id) {
//        //1.从redis中查询缓存
//        String key = CACHE_SHOP_KEY + id;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断缓存是否命中
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.命中
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//
//        }
//        //4.判断命中的是否为空值
//        if ("".equals(shopJson)) {
//            //返回错误信息
//            return null;
//        }
//        //5.实现缓存重建
//        //5.1获取互斥锁
//        String lockKey = LOCK_SHOP_KEY + id;
//        Shop shop = null;
//        try {
//            boolean isLock = tryLock(lockKey);
//            //5.2判断是否获取锁成功
//            if (!isLock) {
//                //5.3失败，休眠并重试
//                TimeUnit.MILLISECONDS.sleep(50);
//                return queryWithMutex(id);
//            }
//            //5.4成功，根据id查询数据库
//            String s = stringRedisTemplate.opsForValue().get(key);
//            if (s != null) {
//                shop = JSONUtil.toBean(s, Shop.class);
//                return shop;
//            }
//            shop = getById(id);
//
//
//            //6.不存在，返回404，结束
//            if (shop == null) {
//                //将空值写入redis，防止缓存穿透
//                stringRedisTemplate.opsForValue().set(key, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
//                //返回错误信息
//                return null;
//            }
//            //7.存在，将商铺数据写入redis
//            stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        } catch (InterruptedException e) {
//            throw new RuntimeException(e);
//        } finally {
//            //8.释放互斥锁
//            unLock(lockKey);
//        }
//
//        //9.返回商铺信息，结束
//        return shop;
//    }

    /**
     * queryWithPassThrough(Long id)方法是用来解决缓存穿透问题的
     *
     * @param id
     * @return
     */
    //    public Shop queryWithPassThrough(Long id) {
//
//        //1.从redis中查询缓存
//        String key = CACHE_SHOP_KEY + id;
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断缓存是否命中
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.命中
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//
//        }
//        //4.未命中(判断命中的是否为空值) "".equals(shopJson)
//        /**
//         * 当第一次访问到不存在的数据时，下面这个判断shopJson != null是不会通过的，然后会缓存空对象
//         * 第二次访问时，shopJson为“”但是不是null，所以会进入下面的判断
//         */
//        if ("".equals(shopJson)) {
//            //返回错误信息
//            return null;
//        }
//        //5.根据id查询数据库
//        Shop shop = getById(id);
//        //6.判断商铺是否存在
//        //7.不存在，返回404，结束
//        if (shop == null) {
//            //将空值写入redis，防止缓存穿透
//            stringRedisTemplate.opsForValue().set(key, "", 2L, TimeUnit.MINUTES);
//            //返回错误信息
//            return null;
//        }
//        //8.存在，将商铺数据写入redis
//        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop), CACHE_NULL_TTL, TimeUnit.MINUTES);
//
//        //9.返回商铺信息，结束
//        return shop;
//    }

//    private boolean tryLock(String key) {
//        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10L, TimeUnit.SECONDS);
//        return BooleanUtil.isTrue(flag);
//    }

//    private void unLock(String key) {
//        stringRedisTemplate.delete(key);
//    }

//    public void saveShop2Redis(Long id, Long expireSeconds) throws InterruptedException {
//        //1.查询店铺数据
//        Shop shop = getById(id);
//        TimeUnit.MILLISECONDS.sleep(200);
//        //2.封装逻辑过期时间
//        RedisData redisData = new RedisData();
//        redisData.setData(shop);
//        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
//        //3.写入redis
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(redisData));
//    }

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("店铺id不存在");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否需要按照坐标查询
        if (x==null || y == null){
            //不需要进行地理查询，直接数据库查询
            Page<Shop> page = query().eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            //返回数据
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        //3.查询redis，按照距离排序，分页，结果：shopId distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
                );
        //4.解析出id
        if (results == null){
            return Result.ok();
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        List<Long> ids = new ArrayList<>(list.size());
        Map<String,Distance> distanceMap = new HashMap<>(list.size());
        //4.1.截取from——end的部分
        if (list.size() <= from){
            return Result.ok(Collections.emptyList());
        }
        list.stream().skip(from).forEach(result -> {
            //4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3.获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //5.根据id查询店铺
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("order by field( id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }

        //6.返回
        return Result.ok(shops);
    }
}
